66
12. Heating at Low Thermal Output
The thermal output of your Lisboa stove is primarily affected by the quantity of fuel used.
Do not attempt to slow down the combustion by reducing the air supply. When
heating with wood, this can result in an incomplete burning process and pose the
risk of explosive-like combustion of the accumulated wood gases (deflagration).
12.1 Heating with briquettes at lowest thermal output
13. Emptying the Ash Drawer
For safety‘s sake, please make sure that you only dispose of ashes once they are cold. While
the ash collects, the lid is located under the ash drawer.
Unlock the ash drawer. Remove both the ash drawer and the lid located underneath it.
Slide the lid onto the ash drawer so that it is closed; this prevents ashes from flying around,
which in turn means your home stays clean. To place the ash drawer back into the stove,
proceed in the reverse order.
Piled up ashes can prevent or even block the primary air supply to the stove.
Ensure that the ventilation path for the primary air between the ash drawer and
the bottom of the ash compartment remains clear.
14. The Combustion Process
A piece of wood burns in three phases. In a wood fire, however, these processes take place
both consecutively and simultaneously
14.1 Drying Phase
The moisture still remaining in the air-dried wood (approx. 15 - 20%) is evaporated.
This takes place at temperatures of approx. 100°C. For the evaporation to occur, the wood
must be supplied with heat during the warming up phase; this is achieved by using small
wood logs.
14.2 Degasification Phase
At temperatures of between 100°C and 150°C, the contents of the wood start (slowly at
first) to disintegrate and gasify and the wood begins its thermal decomposition. At tem-
peratures above 150°C, the gas development increases strongly. The proportion of volatile
components makes up around 80% of the wood substance.
Procedure
Position of control elements
Close shaking grate
Push shaking grate slide in
Close heating-up air slide
Move primary air damper (I)
all the way to the right.
Set secondary air
Set secondary air slide (II) at position two
Add two logs of wood
(a ca. 0.4 kg) lengthways
Procedure
Position of control elements
Place one briquette on shaking grate
Open shaking grate
Pull out shaking grate slide
Set heating-up air
Set heating-up air slide (I)
on second groove
Set secondary air
Set secondary air slide (II)
to second groove
